Atoms — Physics STD 12 Science — Question

Which logic gate produces LOW output when any of the inputs is HIGH?

Suppose, the electron in a hydrogen atom makes transition from n = 3 to n = 2 in 10^-8s. The order of the torque acting on the electron in this period, using the relation between torque and angular momentum as discussed in the chapter on rotational mechanics is:

1. 10^-34Nm
2. 10^-24Nm
3. 10^-42Nm
4. 10^-8Nm

When an electron strikes the target in a Coolidge tube, its entire kinetic energy:

1. Is converted into a photon.
2. May be converted into a photon.
3. Is converted into heat.
4. May be converted into heat.

A light source approaches the observer with velocity 0.8 c. The doppler shift for the light of wavelength  5500 Å is

(a) 4400 Å

(b) 1833 Å

(c) 3167 Å

(d) 7333 Å

The magnet can be completely demagnetized by

(a) Breaking the magnet into small pieces

(b) Heating it slightly

(c) Droping it into ice cold water

(d) A reverse field of appropriate strength

A constant current i is maintained in a solenoid. Which of the following quantities will increase if an iron rod is inserted in the soleniod along axis?

................. gave the principle of Electromagnetic Induction.

Light of frequency 4n₀ is incident on the metal of the threshold frequency n₀. The maximum kinetic energy of the emitted photoelectrons is

(a)

(b)

(c)

(d)

Magnetic moments of two bar magnets may be compared with the help of

(a)  Deflection magnetometer	(b) Vibration magnetometer
(c) Both of the above	(d) None of the above

Which theory of light explains the photoelectric effect?